The food packaging industry uses packaging films from which bags and casings are made which are such that they may be used in cook-in applications, i.e., uses in which a food product is packaged in the film, following which the food product is cooked while packaged in the film. The term “cook-in,” as used herein with respect to packaging materials such as films, refers to packaging material structurally capable of withstanding exposure to cook-in time-temperature conditions while surrounding a food product. Cook-in foods are foods cooked in the package. The cooked product can be distributed to the customer in the original bag or the bag removed and the meat portioned for repackaging. Cook-in time-temperature conditions typically refer to a long slow cook, for example submersion in hot water at 131° F. to 149° F. for 12 hours. However, cook-in can include submersion at from 135° F. to 212° F. for 2–12 hours, or from 158° F. to 212° F. for from 1–4 hours.
During cook-in, the package should maintain seal integrity, i.e., any heat-sealed seams should resist being pulled apart during cook-in. Preferably, the film is heat sealable to itself Additionally, the packaging film substantially conforms to the packaged food product. Preferably, this substantial conformability is achieved by the film being heat shrinkable under these conditions so as to form a tightly fitting package. In other words, in an advantageous embodiment, the film is heat-shrinkable under time-temperature conditions of cook-in, i.e., the film possesses sufficient shrink energy such that submerging the packaged food product in hot water will shrink the packaging film snugly around the packaged product, representatively up to about 55% monoaxial or biaxial shrinkage at 185° F. Also, during cook-in the film should have food product adherence to restrict “cook-out,” i.e., the collection of juices between the surface of the contained food product and the meat-contact surface of the packaging material; cook-out is commonly referred to as “purge.” In this manner, product yield is increased by the food product retaining moisture, and the aesthetic appearance of the packaged product is not diminished by the presence of the purge.
For ham, beef, turkey, and other meat products, it is often desirable to expose the surface of the meat product to an additive, to simply coat or even suffuse the additive into the surface of the meat product. The additive can be, for example, a colorant or flavorant. The use of a smoke-containing additive is particularly common, the smoke providing both a flavor effect and a color effect to the meat product.
If the surface of the product is to be exposed to an additive, for example to produce a smoked meat product, it has for some time been standard practice in the industry to first package the meat product in a film, followed by cooking the meat product while it is packaged, followed by removing the cooked meat from the package and placing the meat in a smokehouse to impart smoke coloration and flavor. The smoked meat product is thereafter repackaged in another film, and shipped to a wholesaler, retailer, or consumer.
In addition, the unpackaging, smoking, and repackaging of the cooked meat product exposes the cooked meat product to microbial contamination, resulting in shorter shelf life for the cooked meat product. However, the need to unpackage, smoke, and repackage the meat product is a labor intensive, expensive process for the manufacturer of the smoked cooked meat product. Furthermore, the smoking step is inefficient in that only about 70% of the smoke is effective as a flavorant/colorant, with the remaining 30% of the smoke accumulating on non-food surfaces in the smokehouse, necessitating cleaning, etc. and generating waste.
Thus, it would be desirable to provide a packaged product without having to package, cook, unpackage, smoke, and repackage, together with avoiding the handling required for each of these operations. It would be desirable to entirely avoid the need to unpackage and repackage and thereby avoid the potential for microbiological contamination, together with avoiding the waste from discarding the original package, the inefficiency and waster from the smoking in a smokehouse, as well as to avoid the lower shelf life of the finally-packaged product, resulting from microbiological contamination due to excess handling of the cooked meat product.